1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/hfsplus/unicode.c
4 *
5 * Copyright (C) 2001
6 * Brad Boyer (flar@allandria.com)
7 * (C) 2003 Ardis Technologies <roman@ardistech.com>
8 *
9 * Handler routines for unicode strings
10 */
11
12 #include <linux/types.h>
13 #include <linux/nls.h>
14 #include "hfsplus_fs.h"
15 #include "hfsplus_raw.h"
16
17 /* Fold the case of a unicode char, given the 16 bit value */
18 /* Returns folded char, or 0 if ignorable */
19 static inline u16 case_fold(u16 c)
20 {
21 u16 tmp;
22
23 tmp = hfsplus_case_fold_table[c >> 8];
24 if (tmp)
25 tmp = hfsplus_case_fold_table[tmp + (c & 0xff)];
26 else
27 tmp = c;
28 return tmp;
29 }
30
31 /* Compare unicode strings, return values like normal strcmp */
32 int hfsplus_strcasecmp(const struct hfsplus_unistr *s1,
33 const struct hfsplus_unistr *s2)
34 {
35 u16 len1, len2, c1, c2;
36 const hfsplus_unichr *p1, *p2;
37
38 len1 = be16_to_cpu(s1->length);
39 len2 = be16_to_cpu(s2->length);
40 p1 = s1->unicode;
41 p2 = s2->unicode;
42
43 while (1) {
44 c1 = c2 = 0;
45
46 while (len1 && !c1) {
47 c1 = case_fold(be16_to_cpu(*p1));
48 p1++;
49 len1--;
50 }
51 while (len2 && !c2) {
52 c2 = case_fold(be16_to_cpu(*p2));
53 p2++;
54 len2--;
55 }
56
57 if (c1 != c2)
58 return (c1 < c2) ? -1 : 1;
59 if (!c1 && !c2)
60 return 0;
61 }
62 }
63
64 /* Compare names as a sequence of 16-bit unsigned integers */
65 int hfsplus_strcmp(const struct hfsplus_unistr *s1,
66 const struct hfsplus_unistr *s2)
67 {
68 u16 len1, len2, c1, c2;
69 const hfsplus_unichr *p1, *p2;
70 int len;
71
72 len1 = be16_to_cpu(s1->length);
73 len2 = be16_to_cpu(s2->length);
74 p1 = s1->unicode;
75 p2 = s2->unicode;
76
77 for (len = min(len1, len2); len > 0; len--) {
78 c1 = be16_to_cpu(*p1);
79 c2 = be16_to_cpu(*p2);
80 if (c1 != c2)
81 return c1 < c2 ? -1 : 1;
82 p1++;
83 p2++;
84 }
85
86 return len1 < len2 ? -1 :
87 len1 > len2 ? 1 : 0;
88 }
89
90
91 #define Hangul_SBase 0xac00
92 #define Hangul_LBase 0x1100
93 #define Hangul_VBase 0x1161
94 #define Hangul_TBase 0x11a7
95 #define Hangul_SCount 11172
96 #define Hangul_LCount 19
97 #define Hangul_VCount 21
98 #define Hangul_TCount 28
99 #define Hangul_NCount (Hangul_VCount * Hangul_TCount)
100
101
102 static u16 *hfsplus_compose_lookup(u16 *p, u16 cc)
103 {
104 int i, s, e;
105
106 s = 1;
107 e = p[1];
108 if (!e || cc < p[s * 2] || cc > p[e * 2])
109 return NULL;
110 do {
111 i = (s + e) / 2;
112 if (cc > p[i * 2])
113 s = i + 1;
114 else if (cc < p[i * 2])
115 e = i - 1;
116 else
117 return hfsplus_compose_table + p[i * 2 + 1];
118 } while (s <= e);
119 return NULL;
120 }
121
122 int hfsplus_uni2asc(struct super_block *sb,
123 const struct hfsplus_unistr *ustr,
124 char *astr, int *len_p)
125 {
126 const hfsplus_unichr *ip;
127 struct nls_table *nls = HFSPLUS_SB(sb)->nls;
128 u8 *op;
129 u16 cc, c0, c1;
130 u16 *ce1, *ce2;
131 int i, len, ustrlen, res, compose;
132
133 op = astr;
134 ip = ustr->unicode;
135 ustrlen = be16_to_cpu(ustr->length);
136 len = *len_p;
137 ce1 = NULL;
138 compose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
139
140 while (ustrlen > 0) {
141 c0 = be16_to_cpu(*ip++);
142 ustrlen--;
143 /* search for single decomposed char */
144 if (likely(compose))
145 ce1 = hfsplus_compose_lookup(hfsplus_compose_table, c0);
146 if (ce1)
147 cc = ce1[0];
148 else
149 cc = 0;
150 if (cc) {
151 /* start of a possibly decomposed Hangul char */
152 if (cc != 0xffff)
153 goto done;
154 if (!ustrlen)
155 goto same;
156 c1 = be16_to_cpu(*ip) - Hangul_VBase;
157 if (c1 < Hangul_VCount) {
158 /* compose the Hangul char */
159 cc = (c0 - Hangul_LBase) * Hangul_VCount;
160 cc = (cc + c1) * Hangul_TCount;
161 cc += Hangul_SBase;
162 ip++;
163 ustrlen--;
164 if (!ustrlen)
165 goto done;
166 c1 = be16_to_cpu(*ip) - Hangul_TBase;
167 if (c1 > 0 && c1 < Hangul_TCount) {
168 cc += c1;
169 ip++;
170 ustrlen--;
171 }
172 goto done;
173 }
174 }
175 while (1) {
176 /* main loop for common case of not composed chars */
177 if (!ustrlen)
178 goto same;
179 c1 = be16_to_cpu(*ip);
180 if (likely(compose))
181 ce1 = hfsplus_compose_lookup(
182 hfsplus_compose_table, c1);
183 if (ce1)
184 break;
185 switch (c0) {
186 case 0:
187 c0 = 0x2400;
188 break;
189 case '/':
190 c0 = ':';
191 break;
192 }
193 res = nls->uni2char(c0, op, len);
194 if (res < 0) {
195 if (res == -ENAMETOOLONG)
196 goto out;
197 *op = '?';
198 res = 1;
199 }
200 op += res;
201 len -= res;
202 c0 = c1;
203 ip++;
204 ustrlen--;
205 }
206 ce2 = hfsplus_compose_lookup(ce1, c0);
207 if (ce2) {
208 i = 1;
209 while (i < ustrlen) {
210 ce1 = hfsplus_compose_lookup(ce2,
211 be16_to_cpu(ip[i]));
212 if (!ce1)
213 break;
214 i++;
215 ce2 = ce1;
216 }
217 cc = ce2[0];
218 if (cc) {
219 ip += i;
220 ustrlen -= i;
221 goto done;
222 }
223 }
224 same:
225 switch (c0) {
226 case 0:
227 cc = 0x2400;
228 break;
229 case '/':
230 cc = ':';
231 break;
232 default:
233 cc = c0;
234 }
235 done:
236 res = nls->uni2char(cc, op, len);
237 if (res < 0) {
238 if (res == -ENAMETOOLONG)
239 goto out;
240 *op = '?';
241 res = 1;
242 }
243 op += res;
244 len -= res;
245 }
246 res = 0;
247 out:
248 *len_p = (char *)op - astr;
249 return res;
250 }
251
252 /*
253 * Convert one or more ASCII characters into a single unicode character.
254 * Returns the number of ASCII characters corresponding to the unicode char.
255 */
256 static inline int asc2unichar(struct super_block *sb, const char *astr, int len,
257 wchar_t *uc)
258 {
259 int size = HFSPLUS_SB(sb)->nls->char2uni(astr, len, uc);
260 if (size <= 0) {
261 *uc = '?';
262 size = 1;
263 }
264 switch (*uc) {
265 case 0x2400:
266 *uc = 0;
267 break;
268 case ':':
269 *uc = '/';
270 break;
271 }
272 return size;
273 }
274
275 /* Decomposes a non-Hangul unicode character. */
276 static u16 *hfsplus_decompose_nonhangul(wchar_t uc, int *size)
277 {
278 int off;
279
280 off = hfsplus_decompose_table[(uc >> 12) & 0xf];
281 if (off == 0 || off == 0xffff)
282 return NULL;
283
284 off = hfsplus_decompose_table[off + ((uc >> 8) & 0xf)];
285 if (!off)
286 return NULL;
287
288 off = hfsplus_decompose_table[off + ((uc >> 4) & 0xf)];
289 if (!off)
290 return NULL;
291
292 off = hfsplus_decompose_table[off + (uc & 0xf)];
293 *size = off & 3;
294 if (*size == 0)
295 return NULL;
296 return hfsplus_decompose_table + (off / 4);
297 }
298
299 /*
300 * Try to decompose a unicode character as Hangul. Return 0 if @uc is not
301 * precomposed Hangul, otherwise return the length of the decomposition.
302 *
303 * This function was adapted from sample code from the Unicode Standard
304 * Annex #15: Unicode Normalization Forms, version 3.2.0.
305 *
306 * Copyright (C) 1991-2018 Unicode, Inc. All rights reserved. Distributed
307 * under the Terms of Use in http://www.unicode.org/copyright.html.
308 */
309 static int hfsplus_try_decompose_hangul(wchar_t uc, u16 *result)
310 {
311 int index;
312 int l, v, t;
313
314 index = uc - Hangul_SBase;
315 if (index < 0 || index >= Hangul_SCount)
316 return 0;
317
318 l = Hangul_LBase + index / Hangul_NCount;
319 v = Hangul_VBase + (index % Hangul_NCount) / Hangul_TCount;
320 t = Hangul_TBase + index % Hangul_TCount;
321
322 result[0] = l;
323 result[1] = v;
324 if (t != Hangul_TBase) {
325 result[2] = t;
326 return 3;
327 }
328 return 2;
329 }
330
331 /* Decomposes a single unicode character. */
332 static u16 *decompose_unichar(wchar_t uc, int *size, u16 *hangul_buffer)
333 {
334 u16 *result;
335
336 /* Hangul is handled separately */
337 result = hangul_buffer;
338 *size = hfsplus_try_decompose_hangul(uc, result);
339 if (*size == 0)
340 result = hfsplus_decompose_nonhangul(uc, size);
341 return result;
342 }
343
344 int hfsplus_asc2uni(struct super_block *sb,
345 struct hfsplus_unistr *ustr, int max_unistr_len,
346 const char *astr, int len)
347 {
348 int size, dsize, decompose;
349 u16 *dstr, outlen = 0;
350 wchar_t c;
351 u16 dhangul[3];
352
353 decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
354 while (outlen < max_unistr_len && len > 0) {
355 size = asc2unichar(sb, astr, len, &c);
356
357 if (decompose)
358 dstr = decompose_unichar(c, &dsize, dhangul);
359 else
360 dstr = NULL;
361 if (dstr) {
362 if (outlen + dsize > max_unistr_len)
363 break;
364 do {
365 ustr->unicode[outlen++] = cpu_to_be16(*dstr++);
366 } while (--dsize > 0);
367 } else
368 ustr->unicode[outlen++] = cpu_to_be16(c);
369
370 astr += size;
371 len -= size;
372 }
373 ustr->length = cpu_to_be16(outlen);
374 if (len > 0)
375 return -ENAMETOOLONG;
376 return 0;
377 }
378
379 /*
380 * Hash a string to an integer as appropriate for the HFS+ filesystem.
381 * Composed unicode characters are decomposed and case-folding is performed
382 * if the appropriate bits are (un)set on the superblock.
383 */
384 int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str)
385 {
386 struct super_block *sb = dentry->d_sb;
387 const char *astr;
388 const u16 *dstr;
389 int casefold, decompose, size, len;
390 unsigned long hash;
391 wchar_t c;
392 u16 c2;
393 u16 dhangul[3];
394
395 casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
396 decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
397 hash = init_name_hash(dentry);
398 astr = str->name;
399 len = str->len;
400 while (len > 0) {
401 int dsize;
402 size = asc2unichar(sb, astr, len, &c);
403 astr += size;
404 len -= size;
405
406 if (decompose)
407 dstr = decompose_unichar(c, &dsize, dhangul);
408 else
409 dstr = NULL;
410 if (dstr) {
411 do {
412 c2 = *dstr++;
413 if (casefold)
414 c2 = case_fold(c2);
415 if (!casefold || c2)
416 hash = partial_name_hash(c2, hash);
417 } while (--dsize > 0);
418 } else {
419 c2 = c;
420 if (casefold)
421 c2 = case_fold(c2);
422 if (!casefold || c2)
423 hash = partial_name_hash(c2, hash);
424 }
425 }
426 str->hash = end_name_hash(hash);
427
428 return 0;
429 }
430
431 /*
432 * Compare strings with HFS+ filename ordering.
433 * Composed unicode characters are decomposed and case-folding is performed
434 * if the appropriate bits are (un)set on the superblock.
435 */
436 int hfsplus_compare_dentry(const struct dentry *dentry,
437 unsigned int len, const char *str, const struct qstr *name)
438 {
439 struct super_block *sb = dentry->d_sb;
440 int casefold, decompose, size;
441 int dsize1, dsize2, len1, len2;
442 const u16 *dstr1, *dstr2;
443 const char *astr1, *astr2;
444 u16 c1, c2;
445 wchar_t c;
446 u16 dhangul_1[3], dhangul_2[3];
447
448 casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
449 decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
450 astr1 = str;
451 len1 = len;
452 astr2 = name->name;
453 len2 = name->len;
454 dsize1 = dsize2 = 0;
455 dstr1 = dstr2 = NULL;
456
457 while (len1 > 0 && len2 > 0) {
458 if (!dsize1) {
459 size = asc2unichar(sb, astr1, len1, &c);
460 astr1 += size;
461 len1 -= size;
462
463 if (decompose)
464 dstr1 = decompose_unichar(c, &dsize1,
465 dhangul_1);
466 if (!decompose || !dstr1) {
467 c1 = c;
468 dstr1 = &c1;
469 dsize1 = 1;
470 }
471 }
472
473 if (!dsize2) {
474 size = asc2unichar(sb, astr2, len2, &c);
475 astr2 += size;
476 len2 -= size;
477
478 if (decompose)
479 dstr2 = decompose_unichar(c, &dsize2,
480 dhangul_2);
481 if (!decompose || !dstr2) {
482 c2 = c;
483 dstr2 = &c2;
484 dsize2 = 1;
485 }
486 }
487
488 c1 = *dstr1;
489 c2 = *dstr2;
490 if (casefold) {
491 c1 = case_fold(c1);
492 if (!c1) {
493 dstr1++;
494 dsize1--;
495 continue;
496 }
497 c2 = case_fold(c2);
498 if (!c2) {
499 dstr2++;
500 dsize2--;
501 continue;
502 }
503 }
504 if (c1 < c2)
505 return -1;
506 else if (c1 > c2)
507 return 1;
508
509 dstr1++;
510 dsize1--;
511 dstr2++;
512 dsize2--;
513 }
514
515 if (len1 < len2)
516 return -1;
517 if (len1 > len2)
518 return 1;
519 return 0;
520 }
521
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